1. Field of the Invention
The present invention relates generally to vibratory bowl feeders and, more specifically, to a vibratory bowl which is equipped with an automatic cleanout feature that empties the contents from the bowl with minimal operator interaction.
2. Description of the Prior Art
Vibratory bowl feeders have been known for many years in the fields of automatic assembly and manufacturing. Those skilled in the art of automatic assembly are also very much aware of the many different types of adaptations of vibratory bowls that have been provided to meet the needs of the many specific applications with which they are used. For example, U.S. Pat. No. 5,114,039, which issued to Walshe et al on May 19, 1992, describes an apparatus and method for discharging articles from a vibratory feeder. The apparatus is specifically used for transferring flanged articles from a vibratory feeder to a discharge station which features a pair of feed rails. One of the rails has a curved external surface for providing point bearing contact with a flange of the article being transferred.
U.S. Pat. No. 4,721,228, which issued to Bejerano on Jan. 26, 1988, discloses an apparatus for dispensing elongated small mechanical parts. It comprises a component handling assembly and a buffer assembly. The component handling assembly receives bulk quantities of the components and, when activated, properly orients each component and supplies the components in a randomly timed sequence to the buffer assembly. The buffer assembly comprises a cylindrical upper receiving housing having a plurality of cylindrical chambers radially disposed in a circular pattern and rotatable about a central generally vertical axis.
U.S. Pat. No. 4,852,771, which issued to Kando on Aug. 1, 1989, describes a parts supply hopper that is operatively associated with a parts feeder for supplying the latter with a predetermined amount of articles. It includes a generally cup-shaped container held in an angular position and rotatable at least through an angle of 180 degrees and a partition wall disposed with the container so as to define therebetween upper and lower chambers disposed on opposite sides of the partition wall.
U.S. Pat. No. 4,878,575, which issued to McDonald et al on Nov. 7, 1989, discloses a vibratory feeder for elastomeric components. The apparatus is provided with a means for accepting an initially presented population of randomly oriented articles formed from a soft elastomeric material. It provides a high speed output stream wherein all of said articles are commonly oriented for further mechanical manipulation. The apparatus includes an input bowl for accepting the articles. The bowl includes a rotatable central disc for feeding objects incident thereupon to the periphery of the disc.
U.S. Pat. No. 4,905,416, which issued to Harley on Mar. 6, 1990, describes a reversing weight assembly for a vibratory bowl finishing machine. It includes a dampening housing attached to the upper end of a drive shaft for the machine. The housing is filled with dampening material such as a viscous fluid and includes a freely rotatable damping vane inside the housing. The vane is connectable to an upper eccentric weight which is rotatable in correspondence with rotation of the dampening vane.
U.S. Pat. No. 4,732,258, which issued to Burgess, Jr. on Mar. 11, 1988, describes a vibratory work station module and system. The module includes a buffer storage area for transitory storage of work piece carriers which are received at non-specific intervals and an escapement station to facilitate performance of some operation of a work piece carried by each carrier. The buffer storage area includes a conveying surface which is defined by a multiplicity of fibers and which is vibrated to move the carriers longitudinally therealong. The resiliency of the fibers permits carriers which are adjacent the escapement station to remain stationary even though the conveying surface is vibrating.
U.S. Pat. No. 5,008,580, which issued to Masuda et al on Apr. 16, 1991, discloses a piezoelectric vibration generator and vibratory parts feeder. The generator interconnecting a base and the vibratory conveyor table of a piezoelectrically driven vibratory parts feeder includes a pair of resilient plate members joined together at their lower ends and disposed in a configuration substantially folded about the joint therebetween. The vibration generator of the folded configuration has a relatively small length and hence is capable of reducing the overall height of the vibratory parts feeder.
U.S. Pat. No. 5,078,298, which issued to Omori on Jan. 7, 1992, describes a parts feeding apparatus for use in feeding a supply of garment appliance parts such as buttons, hooks, slide fastener component parts and the like from parts reservoirs or parts feeders through a plurality of feed chutes onto a parts applying holder. The feed chutes each carry thereon an array of parts of different types and colors. The feed chutes are pivotally moveable in the same plane into and out of an operative position relative to the parts applying holder in which position the parts are selectively transferred onto the holder.
In many applications of vibratory feeders, the feeder bowl is filled with parts, or components, that are required in an automatic assembly process. Often, the machinery used to assemble the components can be quickly changed over to assemble other components of alternative design. When this changeover occurs, it is typically necessary for the vibratory bowl feeder to be completely emptied of its existing parts so that parts of a different style or size can be deposited into the bowl feeder in anticipation of the automatic assembly of a new style of component. This is particularly common in the automatic manufacture of components such as switches. When a preselected number of switches is manufactured on an automatic assembly line, the line must be quickly changed over to permit it to begin manufacturing a new style of switch. When this occurs, the plurality of feeder bowls associated with the automatic assembly line must each be emptied and refilled with the appropriate style of component that is suitable for the switch that is to be manufactured.
As is well known to those skilled in the art, the emptying of bowl feeders can be difficult and can require significant time. Some techniques that have been employed in the past include the use of vacuum hoses to remove small components from the bowl, escapement doors formed in the sides of the bowl to permit the bowl to automatically move the parts to the escapement door and permit the parts to drop out through the wall of the bowl or, alternatively, the removal of the parts from the bowl by hand. All of these techniques are disadvantageous in one way or another. The use of a vacuum device to empty a vibratory bowl can damage small and delicate components. The use of the escapement door in the side of a vibratory bowl is extremely slow and can not be depended upon to completely empty the bowl. For example, some parts will continually be caused to fall back into the center of the bowl because of their improper positioning or configuration which does not allow them to move all of the way around the track of the bowl to reach the escapement door. As is well understood by those skilled in the art of vibratory bowl feeders, any mating edges of components within the bowl can cause small parts to snag between the mating edges and other bowl surfaces. During normal operation of a vibratory bowl feeder, these snagged parts can seriously impede the proper operation of the bowl. Therefore, when escapement doors are used in the sides of bowls, significant care must be taken to make sure that the edges of the door meet the edges of the bowl opening and track with significant accuracy to avoid snagging components in the crack therebetween.
The hand removal of parts from a vibratory feeder bowl is also disadvantageous in that it is slow, it can bend and damage delicate components within the bowl and it can contaminate the parts with the natural oils that normally exist on human hands. It would therefore be significantly beneficial to the field of automatic vibratory bowl feeders if a means is developed to rapidly empty the bowl without damaging the parts or contaminating them. It would also be advantages if the bowl cleanout means is automatic and able to remove the contents of the bowl in an expeditious manner with minimum required involvement by the operator.